In this paper a technique that can estimate the required capacity of a Solar Wind Hybrid Power(SWHP) system for an unban residential load is presented. The probability distribution of the power output from SWHP system is calculated from the probability density functions(PDFs) of the solar irradiance and the wind speed for each hour. The size of photovoltaic(PV) array and the number of wind turbines are decided so that the total SWHP system output in one day can meet the total daily residential-load. The available power for battery system charging can be obtained from the difference between the SWHP system generation and the load. Consequently, the distribution of the battery charging power is calculated by convolving the PDFs of both the SWHP system output and the load. A typical local residential load curve is used for illustration and promssing result is obtained.